Cleaning apparatus

ABSTRACT

A system for the removal of accumulations of liquid and fine solid material from between two movable contacting members by a vacuum chamber with a rounded entrance slot and a rubber-like wiper that seals and flicks accumulations off the surface of the members as they move into and out of contact.

Umted States Patent 1191 1111 3,919,737 Riley, Jr. 1451 Nov. 18, 1975 [54] CLEANING APPARATUS 1.120.840 12/1914 Niles 15/306 A x 1,378,278 5/1921 R b rts 15/302 ux [75] Inventor: Bernard James Rlley Oman 2,501.875 3/1950 Rzy urn 15/306 A x 2,818,595 1/1958 ROSWflll.... 15/306 A 3,264,673 8/1966 SCOIII 15/308 [73] Asslgnee' Corporanon Stamford 3,538,535 11/1970 Ginsburgh @1111. 15/302 [22] Filed: 1972 Primary Examiner-Harvey C. Hornsby [21] App]. No,; 248,766 Assistant Examiner-C. K. Moore Related US. Application Data [62] Division of Ser. No. 876,922, Nov. 14, 1969, Pat. No.

[52 us. 01. 15/308 [51] Int. Cl. A47L 5/38 [58] Field of Search 15/302, 306 R, 306 A, 308, 15/321, 322, 401

[56] References Cited UNITED STATES PATENTS 965.315 7/1910 Moorhead 15/322 Attorney, Agent, or Firm.lames J. Ralabate; David C. Petre; Charles E. Smith ABSTRACT A system for the removal of accumulations of liquid and fine solid material from between two movable contacting members by a vacuum chamber with a rounded entrance slot and a rubber-like wiper that seals and flicks accumulations off the surface of the members as they move into and out of contact.

3 Claims, 7 Drawing Figures US. Patent Nov. 18, 1975 Sheet 1 of4 3,919,737

U.S. -Patent Nov. 18, 1975 Sheet2of4 3,919,737

FIG. 2

Patent Nov. 18, 1975 Sheet 3 of 4 FIG. 4

' U.S. Patent Nov. 18, 1975 Sheet4 of4 3,919,737

CLEANING APPARATUS This is a division of application Ser. No. 876,922, filed Nov. 14, 1969, now U.S. Pat. No. 3,686,035.

, This invention relates to cleaning systems and in particular to cleaning systems for removing accumulated materials from between two members.

Apparatus exists today where materials applied to a member of the apparatus tend to accumulate on it. As the member interfaces with other devices moving relative to it, the materials are pushed ahead of the interface area. What generally happens with a liquid and some solid materials is that a major portion of the material is pinched ahead of the nip between the two moving members forming a bead or a large accumulation at the lead edge in the direction of approach of the members. If the bead is allowed to accumulate in front of the approaching devices, it may have deleterious effects upon the apparatus in which it is found. One particular class of apparatus that sometimes encounters this accumulation of materials are hard copy imaging systems. One such system known as photoelectrophoresis is used for forming black and white or full color images. The basic processes and apparatus are disclosed in U.S. Pat. Nos.

3,3 84,565; 3,384,566 and 3,383,993. Since this discovery, various apparatus have been developed to utilize the process disclosed therein.

The basic system utilizes photoelectrophoretic particles which migrate in image configuration providing a visual image at one or both of two electrodes between which the particles are placed in a suspension. The particles are photosensitive and apparently undergo a net change in charge polarity or a polarity alteration by interaction with one of the electrodes upon exposure to activating electromagnetic radiation. The particles will migrate from one of the electrodes under the influence of an electric field when struck with energy of a wavelength within the spectral response of the particles.

Apparatus has been invented to better utilize the above process in an automated system shown in U.S. Pat. No. 3,427,242 issued Feb. 11, 1969 which described a continuous apparatus embodiment of the .above process. Further, equipment has been designed utilizing flat and rotary imaging members to form images with the above process all of which can be improved by the invention herein.

Another system that can be improved by the invention described herein is xerographic imaging where an image is formed and developed on the surface of a photoconductor by electrostatic means. The basic xerographic process as taught by C. F. Carlson in U.S. Pat. No. 2,297,691 involves placing a uniform electrostatic charge on a photoconductive insulating layer, exposing the layer to a light image to dissipate the charge in the areas of the layer exposed to the light and then developing the resulting latent electrostatic image by depositing on the image a finely divided electroscopic material referred to in the art as toner. The toner is attracted normally to those areas of the photoconductive layer which retains a charge thereby forming a toner image corresponding to the electrostatic latent image. The toner image may then be transferred to a support surface and permanently affixed thereto by heat or vapor or the like. It may also be that the photoconductive layer itself serves as the final support medium in which case no transfer step is required.

Many varied methods and apparatus have been designed for developing the latent electrostatic image. Among them are liquid development systems. In conventional liquid development systems an insulating liquid vehicle having finely divided solid material dispersed in it contacts the surface in both charged and uncharged areas but is maintained on the photoconductive surface in a relation to the latent electrostatic image charge pattern thereon. Disclosed in U.S. Pat. No. 3,084,043 is a liquid development system known as polar liquid development. Another development technique is disclosed in U.S. Pat. No. 3,285,714 where an aqueous developer uniformly contacts the entire imag ing surface and selectively wets only the charged areas of the imaging surface.

The liquid developing techniques as well as some dry development techniques often accumulate excess development materials and carriers along the surface of the photoconductive material. It is with these development systems that the invention described herein is a helpful improvement since the developer liquid is loaded onto the applicator surface indiscriminately in excessive quantities. As the developer liquid on the surface of the applicator is brought into contact with the photoconductive surface, it squeezes into a bead at the exit of the nip between the two surfaces. This material is not fully utilized in forming a visible image on the photoconductive surface and it would be helpful to remove the material at least after an image is formed to prevent residual material from interfering with later images to be formed.

Other apparatus can be contemplated such as schematically shown in FIG. 1 hereinafter which uses segments of cylinders in its operation. If the accumulated materials are allowed to ride along the segment, they will eventually leak, drip or fall into the interior of the segment and interfere with the internal mechanism or general operation of the apparatus utilizing such a cylinder segment. Therefore, it becomes important to eliminate accumulations of materials from reaching the edge of segments of cylinders or from continually revolving around a cylindrical or other shaped members.

Therefore, it is an object of this invention to remove accumulations of materials between moving surfaces.

Another object of this invention is to improve cleaning techniques of imaging systems. Yet another object of this invention is to improve development of images. Still another object of this invention is to remove accumulated powders or liquids from between surfaces.

A further object of this invention is to improve systerns for removing accumulations of materials between two moving members cyclically and automatically. Another object of this invention is to prevent accumulation of materials from interfering with further images of an imaging system.

Yet another object of this invention is to remove accumulations of materials between moving surfaces without having additional mechanically moving parts.

These and other objects of this invention are accomplished by providing a vacuum chamber on one of two contacting surfaces, the chamber having an opening and a wiper adjacent the opening to provide both sealing and wiping functions as the surfaces interface with each other with the accumulated material trapped in between them.

The invention herein is described and illustrated in a specific embodiment having specific components listed for carrying out the functions of the apparatus. Nevertheless, the invention need not be thought of as being confined to such a specific showing and should be construed broadly within the scope of the claims. Any and all equivalent structures known to those skilled in the art can be substituted for specific apparatus disclosed as long as the substituted apparatus achieves a similar function. It may be that other processes or apparatus will be invented having similar needs to those fulfilled by the apparatus described and claimed herein and it is the intention herein to describe an invention for use in apparatus other than the embodiment shown.

The above and other objects and advantages of this invention will become apparent to those skilled in the art after reading the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 schematically illustrates an embodiment of a machine for forming photoelectrophoretic images;

FIGS. 2-6 illustrate the sequential operation of the invention; and

FIG. 7 illustrates a partially schematic sectional view of a vacuum circulation system and a perspective view of the vacuum chamber with parts broken away to show hidden features.

A detailed description of the operation and theories pertaining to the actual imaging system shown in FIG. 1 are described in the US. Pat. Nos. 3,384,488; 3,384,565; 3,384,566 and 3,383,993 referred to above. Certain terms referred to therein are adopted herein such as the injecting electrode so named because it is thought to inject electrical charges into activating photosensitive particles during imaging. The term photosensitive refers to the property of a particle which, once attracted to the injecting electrode will alter its polarity and migrate away from the electrode under the influence of an applied electric field when exposed to activating electromagnetic radiation. The term suspension is used here to refer to a solid suspended in a liquid carrier. The termimaging electrode describes that electrode which contacts the injecting electrode through the suspension and which once contacted by activated photosensitive particles will not inject sufficient charge into them to cause them to migrate from the imaging electrode surface. The imaging zone is that zone between two electrodes where photoelectrophoretic imaging occurs.

Briefly, for photoelectrophoretic imaging to occur these steps take place: (I) migration of the photosensitive particles toward the injecting electrode due to the influence of an external field, (2) generation of charge carriers within the particles when struck with activating radiation, (3) particle deposition or near the injecting electrode surface, (4) phenomena associated with the forming of an electrical junction between the particles and the injecting electrode, (5) particle charge exchange with the injecting electrode, (6) electrophoretic migration toward the imaging electrode and (7) particle deposition on the imaging electrode. This leaves a positive image on the injecting electrode.

Referring now to FIG. 1, a preferred embodiment for an automated machine to produce images according to the aforementioned process is shown. An injecting electrode 1 forms a portion of a transparent cylinder member held in a housing 2 and is journaled for rotation in the direction indicated by the arrow about a shaft 3. The injecting electrode 1 is made up of a layer of optically transparent glass 4 overcoated with a thin optically transparent layer 5 of tin oxide or other electrically conducting material. A particular material suit 4 able for this electrode is available under the name of NESA glass manufactured by Pittsburgh Plate ilass Company, Pittsburgh, Pa. The injecting electrode i formed as a portion of a cylinder housed within the metal housing frame 2.

The machine shown schematically in FIG. I is positioned where the injecting electrode cylinder pt: tion is about to be rotated in a predetermined path to a cleaning station labeled A whereat a plurality of cleaning members such as belts 6, 7 and 8 contact the conductive surface 5 of the injecting electrode. On the opposite side of the injecting electrode held stationary within the machine frame are lamps 9, 10 and 11 juxtaposed to the belts 6, 7 and 8 respectively. When activated, the lamps send flood light illumination through the transparent injecting electrode at the contact areas between the electrode and the cleaning belts. Each of the belts are activated by one of the cylinders 12, 13 and 14 to contact the injecting electrode 1. These cylinders operate to press the belts against the conductive surface of the injecting electrode in order to clean it.

The next station in the path of movement of the injecting electrode is the imaging station B. Here, on the first pass of the injecting electrode 1 through station B the first imaging member, the imaging electrode 16 interfaces with the conductive surface 5 of the injecting electrode 1.

The optical system at station C projects an image to the imaging zone between the electrodes 1 and 16 at station B. The optical system has a lamp carriage l7 journaled at an axis 18 to oscillate in a path indicated by the arrows. A document 20 is positioned at the platen 19. The lamps are shown at the start of scan position and as the injecting electrode 1 passes through the imaging area at station E the lamps move across the platen 19 projecting an image at station B through suitable mirrors 21-23, a lens 24 and the transparent electrode l.

The imaging electrode roller 16 moves in rolling interface relation with the conductive surface 5 of the injecting electrode 1 and functions both to supply suspension to the injecting electrode and to image that suspension between the injecting electrode surface 5 and the surface of the electrode 16.

The injecting electrode continues to rotate at a constant velocity through a complete rotation of the predetermined path. It travels without interacting with any elements located around the periphery of the path until it again reaches station E at the imaging zone. Now, however, the injecting electrode 16 has been moved out of its interfacing position by operation of a cylinder 25 which lowers the electrode 16 and the housing 26 supporting it. Further, a cylinder 27 moves a carriage 28 along a horizontal path carrying with it the housing 26 which supports the imaging electrode 16. Also moved in the carriage 28 is a second imaging member, the imaging electrode 29 within a housing 30 maintaining it. A cylinder 31 operates through an eccentric 32 to raise the housing 30 and the second imaging electrode 29 at the imaging zone at the imaging station B of the machine. The second imaging electrode 29 moves in rolling interface with the injecting electrode surface 5 as that surface passes through the imaging station B. At this time the original 20 on the platen 19 is again illuminated by the scanning lamps 33 at the optical system station C. The scan is synchronized with the movement of the injecting electrode to project a flowing image in registration with the first projection and moving at the same rate as is. the surface Sat the imaging zone. 1

The injecting electrode 1 then-passes into the transfer station D. At station D is a transfer roller 40. A sheet of support material held in the supply tray 41 is lifted therefrom and is carried through-a vacuum transport 42.to the transfer roller 40. It is gripped by agripper mechanism-43 on the transfer roller 40 and rotated to the injecting electrode 1 passing-at station D. Before the sheet 44 contacts the surface 5 of the injecting electrode 1 it is moistened witha liquid.that will aidin transferring the particles-of the suspension on the sur- 1 face 5 The wetting is accomplished bya wettingbar 45 rotated in ,a pool of suitable. wetting material held within a tank 46. The transfer member 40 rotates the support material .44. in. rolling contact with the surface 5. of the injecting electrode lander the influence of a suitable electricfield causing the particles. forming the ,image on the injecting electrodeto be transferred to the support material. The supportmaterial is removed from the transfer member by picker fingers 47 and a release mechanism on the grippers. Next it is carried on a vacuum transport 48, to a fixing station E where it is heated or otherwise fixed to form a permanently bonded image onthe support material whichis then, deposited in some suitable receptacle.

Whenever the moving cylinder section 1 interacts with any of the machine components at stations A, B, or D, an accumulation of materials occurs at the exit of the nip formed between the two interfacing members. The imaging suspension 100 is fed from the imaging electrode 16 into the imaging zone or hip between it and the injecting electrode 1. Some ofthe imagi'ngsuspension is carried along the injectingelectrodeas an image to be transferred at the transfer station D where a liquid 102 is applied" to the support surface of a support sheet S so that the image formed from the suspension 100 will more easily transfer'to the support's heet. For illustrative purposes consider the ac't'i ons of the invention in relationto the nip formed between the surface 5'of the injecting'electrode 1 and the surface of the imaging electrode '16; It shouldbe realized; however,

that the actions described in relation to the interface of electrodes 1 and 16 apply equallyto the interface'of the electrodes 1 and the sheets and the cleaning beltsat station A as well as between moving 'surfaces'accumulatingmaterials in other systems.

FIG. 2 shows the bead 104 formed at the exit of the nip between'the cylinder section 1 and the electrode roller 16. The bead runs-alongthefsurface of the housing 2 approaching the curved lip portion 106 of the vacuum chamber 108. A flexible rubber-like wiper blade 112 molded in an L-shape is fastened to the rear wall 114 of the entrance to the vacuum chamber. Be-

tween the curved lip 106 and the wiper blade is an aperture 110 serving as the entrance to the vacuum cham? ber. The housing forming the vacuum chamber 108 has an outer surface 116 which is sunken relative to the wall 117 of housing 2 and the surface 5. This enables the rubber-like wiper 112 to be pressed against the surface 116 in a close but not a substantial interference fit when the interfacing members pass over it. Also and importantly, it prevents contact between the interfacing members and the housing after the accumulated materials have been removed. Hence, no new nips are formed to accumulate more materials. An exhaust tube 118 removes air and accumulated materials from the vacuum chamber 108. A metering strip 120 extends 6t. acrossathe 'entire vacuum chamber and. is used to provide a uniform negative pressureacross the. vacuum chamber 108 and the aperture. during the functional operation of the accumulation removal apparatus.

A few definitions of terms will be helpful to fully understand the meaningand use intended. A negative pressure refers .to a partially evacuated state of less than atmospheric pressure. Similarly, a vacuum? refers to an internal negative pressure below atmospheric pressure but not an absolute void.

FIGS. 3-6 show the sequential operation of the invention as it functions between two moving members, (cylinder section 1 and roller 16). In FIG. 3 the wiper blade 112 prevents the accumulated bead'1 04'from moving along the roll 16 to mix thenew suspension 100 being carried on the surface thereof. As the cylinder section 1 and the roller 16 continue to rotate, a seal is formed between the roller 16 and the housing 2 at one side. of the aperture 110, and the roller 16 and the wiper blade 112 at the other. The ends of the aperture l10are closed by end plates 121 (see FIG. 7) Since this seal exists, as in FIG. 4, it is possible to vacuum out.

the accumulated bead 104 through the vacuum chamber 108 and out of the vicinity of the nip between the two members.

FIG, 5 shows the sequence of events afterthe seal between the drum 1 and roller 16 is broken but as the wiper blade 112. moves to its pre biasedfupright posiv tion after beingpressed against the surface ll6 by the roller 16. The spring action of the rubber-like wiper blade flicks the materials remaining from the'bead off the surface of the roller 116. Under the influence of the negative pressure through the vacuum chamber 108, the remainder of the accumulated bead is pulled into the vacuum chamber and removed from the system..

FIG. 6 shows the end result after breaking contact between the wiper blade and the roller 16. The vacuum chamber continues to pull the materials accumulated therein through it and the roller 16 rotates without further contact of, the cylinder section 1.

Because of the depression of the surface 1 16', relative to the circumference of the cylinder section 1, there is no opportunity for liquid or solid particles to contact the housing 2 from any point' beyond the wiper blade 112. This eliminates the" possibility of accumulating materials after the vacuum cleaning. In the machine environment shown, this brings about the important benefit of preventing accumulated materials from entering the internal portions of the cylinder section where they will interfere with the main processing of the apparatus. The accumulated materials are drawn through the metering strip into the vacuum'chamber 108 via the conduit 118 as shown in FIG. 7. The metering strip 120 has slots 129 of various widths across its length. This is to draw a uniform negative pressure across the length of the vacuum chamber 108 from a vacuum source (pump 137) acting at one end (through the conduit 118) of the chamber 108. A rotary seal 130 connects the rotating conduit 118 to the fixed conduit 131 at the fitting 132 of a vacuum separator 133. The evacuated material passes through the fitting 132 to the vacuum separator 133 where the liquid and air drawn through the vacuum chamber pass through a tube 134 extending partly into the vacuum separator. The liquids and solids drawn into the vacuum separator by the action of the vacuum pump 137 fall to the sump in the bottom thereof where they are accumulated. The air 7 drawn through the system is piped into conduit 136 to the vacuum pump 13 -7 for" removal from the system through an exhaust tube 138. A valve V is fitted on the drain tube 139 and can be opened to enable accumulated liquids and solids to pass into the drain container 140 whenever it is desired.

Of course, the invention can be attached to any roller, flat member, or complete or partial cylindrical or conical member or other member contacted during the operation of the apparatus in which it is housed. It can be used in conjunction with a member over which a sheet or web is passed. The accumulated liquids and solids on the sheet or web accumulated at the nip between -the sheet or web and the member housing the invention will be removed as described above.

One example of an embodiment of this invention is given here without intent or purpose to limit the invention'to the specific dimensions cited.

' The aperture 110 is 0.030 in. wide and 14 inches long (the lengthof the cylinder section 1). The metering stripl extends the 14 inches with 15 slots 120 which are each three-sixteenths in. high and range in width from 0.030 in. at the vacuum connection end to 0.248 in. near the other end. In this embodiment'this achieves the uniform negative pressure discussed above. The vacuum chamber 108 is /8 in. wide, /3 in. high and 14 in. long. The wiper blade is a H16 in. thick polyurethane materialextending three-eighths in. above its preset band. The pump supplies an air flow of 8 ft /min. at a velocity at the aperture of 2740 ft/min.

These dimensions describe only one example of apparatus falling within the scope of the invention and it should be apparent to those skilled in the art that other embodiments within the scope of the invention can be made from the disclosure herein.

While this invention has been described with reference'to the structures disclosed herein and while certain theories have been expressed, it is not confined to the details set forth; and this application is intended to cover such modifications or changes as may come accumulated material cylindrical members c. a slot-formed in the surface of said second cylindrical member extending substantially across said second cylindrical member surface; a chamber within said second cylindrical member and communicating with said slot;

d. means for rotating said first and second cylindrical members relative to each other in rolling contact through said nip in a direction to constrain within said nip accumulated material on at least one of said members;

e. bendable resilient wiper means coupled to an edge of said slot and extending radially with respect to said second cylindrical member, said second cylindrical member having a surface portion adjacent said wiper means lower relative to the first cylindrical member surface than the opposite edge of said slot thereby permitting said wiper meansto bend and be pressed against the surface of the cylindrical members at the nip whenever the advancing cylindrical members pass over said wiper means in interface contact, a seal thereby being formed between said cylindrical members between a curved lip portion of said slot and said first cylindrical member on one side of the slot, and the first cylindrical member and the bent resilient wiper'means at the other side of said slot; vacuum producing means; and

g, means for coupling said vacuum producing means with said chamber and therethrough into said slot said vacuum producing means vacuuming accumulated materials at said nip into said slot, through the slot and therefrom through saidchamber and said coupling means as said slot moves through said nip,

after said slot and said resilient wiper means have passed through said nip, said resilient wiper means providing a flicking action to flick accumulated material, if any, remaining at the nip exit by virtue of the resilient wiper means springing back to an unbent radial position from said first cylindrical member surface. 2. Apparatus accordin g to claim 1 further comprising metering means in said chamber for creating a uniform negative pressure along the length of said slot and wherein said metering means is provided with openings of progressively increasing widths across its length and whereinsaid couplingmeans is coupled to said chamber at the end of the chamber where the openings are smallest. 3. Apparatus according to claim 2 wherein said coupling means is a tube. 

1. Apparatus for removing accumulated material from a nip formed between two cylindrical members comprising; a. a first cylindrical member; b. a second cylindrical member positioned in contact with said first cylindrical member with its axis parallel to the axis of said first cylindrical member to thereby define a nip between said members; c. a slot formed in the surface of said second cylindrical member extending substantially across said second cylindrical member surface; a chamber within said second cylindrical member and communicating with said slot; d. means for rotating said first and second cylindrical members relative to each other in rolling contact through said nip in a direction to constrain within said nip accumulated material on at least one of said members; e. bendable resilient wiper means coupled to an edge of said slot and extending radially with respect to said second cylindrical member, said second cylindrical member having a surface portion adjacent said wiper means lower relative to the first cylindrical member surface than the opposite edge of said slot thereby permitting said wiper means to bend and be pressed against the surface of the cylindrical members at the nip whenever the advancing cylindrical members pass over said wiper means in interface contact, a seal thereby being formed between said cylindrical members between a curved lip portion of said slot and said first cylindrical member on one side of the slot, and the first cylindrical member and the bent resilient wiper means at the other side of said slot; f. vacuum producing means; and g. means for coupling said vacuum producing means with said chamber and therethrough into said slot said vacuum producing means vacuuming accumulated materials at said nip into said slot, through the slot and therefrom through said chamber and said coupling means as said slot moves through said nip, after said slot and said resilient wiper means have passed through said nip, said resilient wiper means providing a flicking action to flick accumulated material, if any, remaining at the nip exit by virtue of the resilient wiper means springing back to an unbent radial position from said first cylindrical member surface.
 2. Apparatus according to claim 1 further comprising metering means in said chamber for creating a uniform negative pressure along the length of said slot and wherein said metering means is provided with openings of progressively increasing widths across its length and wherein said coupling means is coupled to said chamber at the end of the chamber where the openings are smallest.
 3. Apparatus according to claim 2 wherein said coupling means is a tube. 